Anthony, best known for his science fiction (the Xanth series), has based this overburdened saga on early 16th-century artifacts found in an actual North Florida Indian burial mound. Combining myth, fantasy and history, this wide-ranging, picaresque adventure follows the 15-year quest of a young 16th-century Florida Indian, Throat Shot. He has been instructed by spirits of a burial site to save his tribe from a terrible danger by finding the Ulunsuti, a great transparent crystal on the forehead of a snake. The spirits vow to guide him. Throat Shot gamely sets out, encountering a series of colorful traveling companions who either regale him with their own unique stories or pull him into one risky escapade after another. He meets, for example, descendants of Mayan royalty; he escapes Aztecs bent on extracting his heart. The numerous extraneous narratives slow an already leisurely pace, but the book is yet more seriously marred by the ubiquitous bland tone blanketing every description from that of a smallpox epidemic to that of the encounter with the ultimate enemy, the greedy and arrogant Spanish invaders. (Sept.)